牦牛STAT5A基因组织表达及其突变对乳品质性状的影响

Tissue Expression,Polymorphisms of STAT5A Gene and Their Association with Milk Quality Traits of Yak

信号转导与转录激活因子5A(signal transduction and activator of transcription 5A,STAT5A)作为调控乳蛋白表达的乳腺特异性转录因子,其基因突变影响乳品质性状。本研究应用实时荧光定量PCR(quantitative Real-time PCR,qRT-PCR)检测甘南牦牛STAT5A基因在12个组织中的相对表达量,应用聚合酶链式反应-单链构象多态性(polymerase chain reaction-single strand conformation polymorphism,PCR-SSCP)检测牦牛STAT5A基因多态性,分析基因突变对乳品质性状的影响。结果表明,STAT5A基因在甘南牦牛12个组织中均有表达,在乳腺、心脏、脾脏和肺脏高度表达且显著高于其他组织(p<0.05),在肝脏、皮下脂肪、肾脏、瘤胃、背最长肌和小肠中度表达。本研究在牦牛STAT5A基因exon 5-intron 5、exon 8-intron 8及intron9-exon 10区发现c.606G>A、c.1191+4C>T、c.1194+81T>C和c.1282-38C>T的SNPs表现为中度或低度多态。STAT5A基因突变影响部分胎次甘南牦牛乳品质性状,其中exon 5-intron 5区第3胎基因型B1B1个体及intron 9-exon 10区第2胎A3B3个体乳脂率和总固体物质百分含量均显著高于其他个体(p<0.05),第4胎intron 9-exon 10区基因型A3A3个体乳脂率也显著高于其他个体(p<0.05)。本结果为牦牛乳品质性状的分子遗传研究提供了基础数据。

Signal transduction and activator of transcription 5 A(STAT5A),as a specific transcription factor that regulates lactoprotein expression in breast,plays an important role in milk production traits.In this study,relative expression of STAT5A gene were investigated using Real-time quantitative PCR in 12 tissues of Gannan yak and polymorphisms of this gene were identified by polymerase chain reaction-single strand conformation polymorphism in five yak populations.The association was also analyzed between mutations in STAT5A gene and milk quality traits in Gannan yak.The results showed that the relative expressions of STAT5A gene were different in 12 tissues of Gannan yak that investigated.The higher expression of STAT5A gene were found in mammary gland,heart,spleen and lung,but the moderate expression in liver,subcutaneous fat,kidney,rumen,longissimus dorsi and small intestine.Total of four SNPs were detected in three amplification regions of STAT5A gene(c.606G>A in exon 5,c.1191+4C>T and c.1194+81T>C in intron 8 and c.1282-38C>T in intron 9)and lower or moderately polymorphic were found in five yak populations.The association analysis showed that the variations in STAT5A gene affected the milk quality traits in some parities of Gannan yak.Individuals with genotype B1B1 in third parity yak and A3B3 in second parity yak had significantly higher milk fat rate and total solids percentage than those with other genotypes(p<0.05),as well as yaks with A3A3 in fourth parity had significant higher milk rate than others(p<0.05).These results provide the molecular genetic data for milk quality traits of yak.